There has been known a circuit board having a resin layer and a ceramic layer as a circuit board used for electronic devices.
For example, Japanese Unexamined Patent Publication JP-A 2-253941 (1990) describes a circuit board formed by thermally spraying ceramic on one surface of a metallic foil so as to form a ceramic layer, laminating a prepreg so as to be into contact with the metallic foil on the ceramic layer side, and thermocompressionally molding the laminated body.
However, in general, a ceramic layer and a resin layer are connected together with less adhesion strength. Therefore, when the circuit board is subjected to a stress, the ceramic layer and the resin layer are liable to separate from each other. The accidental separation could lead to a break in wiring, in consequence whereof there results deterioration in the electrical reliability of the circuit board.
As a result, there is a demand for provision of a circuit board for which the electrical reliability is improved.